Merge remote-tracking branch 'remotes/stefanha/tags/fix-buildbot-12082014-pull-request' into staging

Pull request

# gpg: Signature made Thu 28 Aug 2014 13:43:00 BST using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/fix-buildbot-12082014-pull-request:
  Revert "qemu-img: sort block formats in help message"
  block: sort formats alphabetically in bdrv_iterate_format()
  mirror: fix uninitialized variable delay_ns warnings
  trace: avoid Python 2.5 all() in tracetool
  libqtest: launch QEMU with QEMU_AUDIO_DRV=none
  qapi.py: avoid Python 2.5+ any() function

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>